Medical Lead System

This application claims the benefit of U.S. Provisional Application No. 63/347,308, filed May 31, 2022, the disclosure of which is incorporated by reference herein in its entirety.

This disclosure generally relates to an implantable lead system, such as a medical lead for implantation in a heart.

Implantable medical leads may be configured to treat a wide variety of cardiac dysfunctions and can include one or more electrodes and other elements for physiological sensing or therapy delivery. Such leads can allow the electrodes to be positioned at one or more target locations for those functions. An implantable medical lead can be navigated through vasculature of a patient to reach these target locations. An electrode supported by the medical lead may establish electrical communication with tissue of the heart to sense cardiac signals generated by the heart and deliver cardiac pacing to the patient. Evaluation of the target location is often conducted to determine a satisfactory location for the electrode within the heart to provide adequate activation of the cardiac system.

The techniques of this disclosure generally relate to a medical lead system and an implantable medical device assembly that includes such lead system. The system can include a lead having a distal balloon connected to an exterior surface of a distal end of a lead body of the lead. The distal balloon can be fluidly connected to an outlet of a lumen of the lead. The system can also include a pressure sensor that is fluidly connected to an inlet of the lumen of the lead. The pressure sensor can be configured to sense pressure within an interior volume of the distal balloon and communicate a signal that is indicative of such pressure to a clinician. In one or more embodiments, the system can also include an inflation mechanism configured to be fluidly connected to the inlet of the lumen of the lead body and manipulate the distal balloon between the deflated configuration and the inflated configuration. The pressure sensor can include any suitable sensor. In one or more embodiments, the pressure sensor can include an indicator balloon that defines a deflated configuration and an inflated configuration. The indicator balloon can be in the deflated configuration when the distal balloon is in the deflated configuration. Further, the indicator balloon can be in the inflated configuration when the distal balloon is in the inflated configuration.

This disclosure includes without limitation the following clauses:

Clause 1: A medical lead system that includes a lead. The lead includes a lead body that has a distal end configured to extend through vasculature to a chamber of a heart of a patient, where the lead body further includes a lumen that extends along the lead body between an inlet adjacent to a proximal end of the lead body and an outlet adjacent to the distal end of the lead body; a fixation member configured to extend distal to the distal end of the lead body, where the fixation member is configured to be secured to tissue of the heart; and a distal balloon connected to an exterior surface of the distal end of the lead body and fluidly connected to the outlet of the lumen, where the distal balloon defines a deflated configuration and an inflated configuration, and further where the distal balloon is configured to expand radially outward from the exterior surface of the lead body and extend distally beyond the distal end of the lead body when the distal balloon inflates from the deflated configuration to the inflated configuration. The medical lead system further includes a pressure sensor fluidly connected to the inlet of the lumen of the lead body and configured to sense a pressure within an interior volume of the distal balloon and communicate a signal indicative of the pressure to a clinician. The fixation member is further configured to extend distal to the distal balloon when the distal balloon is in the inflated configuration.

Clause 2: The system of Clause 1, further including an inflation mechanism configured to be fluidly connected to the inlet of the lumen of the lead body and manipulate the distal balloon between the deflated configuration and the inflated configuration.

Clause 3: The system of Clause 2, where the inflation mechanism includes a syringe or a pump.

Clause 4: The system of any one of Clauses 2-3, where the pressure sensor is connected to the inflation mechanism.

Clause 5: The system of any one of Clauses 1-4, where the pressure sensor includes an indicator balloon that defines a deflated configuration and an inflated configuration, where the indicator balloon is in the deflated configuration when the distal balloon is in the deflated configuration, and further where the indicator balloon is in the inflated configuration when the distal balloon is in the inflated configuration.

Clause 6: The system of any one of Clauses 1-4, where the pressure sensor includes a disk and a base configured to receive the disk, where a major surface of the disk faces a major surface of the base, where the signal includes a first configuration and a second configuration of the disk, where a first distance between a center portion of the major surface of the disk and the major surface of the base when the disk is in the first configuration as measured along a normal to the major surface of the disk and major surface of the base is less than a second distance between the center portion of the major surface of the disk and the major surface of the base when the disk is in the second configuration. The disk is in the first configuration when the distal balloon is in the deflated configuration and in the second configuration when the distal balloon is in the inflated configuration.

Clause 7: The system of any one of Clauses 1-4, where the pressure sensor includes a pressure transducer.

Clause 8: The system of any of Clauses 1-4, where the pressure sensor includes an audible alarm.

Clause 9: The system of any one of Clauses 1-4, where the pressure sensor includes an indicator light, where the indicator light is configured to emit light including a first wavelength when the distal balloon is in the deflated configuration and emit light including a second wavelength when the distal balloon is in the inflated configuration.

Clause 10: The system of any one of Clauses 1-4, where the pressure sensor includes a colored diaphragm and a frosted lens, where the colored diaphragm is configured to move in a direction normal to the diaphragm and frosted lens. A contact area between the colored diaphragm and the frosted lens corresponds to a pressure within the interior volume of the distal balloon.

Clause 11: The system of any one of Clauses 1-4, where the pressure sensor includes a mechanical switch, where the signal includes a change of shape of the mechanical switch.

Clause 12: An implantable medical device assembly that includes an implantable medical device having a housing and an electronics module disposed within the housing and including a power source and circuitry electrically connected to the power source. The assembly further includes a lead system. The lead system includes a lead that includes a lead body having a distal end configured to extend through vasculature to a chamber of a heart of a patient, where the lead body includes a lumen that extends along the lead body between an inlet adjacent to a proximal end of the lead body and an outlet adjacent to the distal end of the lead body, where at least a proximal portion of the lead body is configured to be inserted into a lead bore of the housing; a fixation member configured to extend distal to the distal end of the lead body, where the fixation member is configured to secure to tissue of the heart; and a distal balloon connected to an exterior surface of the distal end of the lead body and fluidly connected to the outlet of the lumen, where the distal balloon defines a deflated configuration and an inflated configuration, and further where the distal balloon is configured to expand radially outward from the exterior surface of the lead body and extend distally beyond the distal end of the lead body when the distal balloon inflates from the deflated configuration to the inflated configuration. The lead system further includes a pressure sensor fluidly connected to the inlet of the lumen of the lead body and configured to sense a pressure within an interior volume of the distal balloon and communicate a signal indicative of the pressure to a clinician. The fixation member is configured to extend distal to the distal balloon when the distal balloon is in the inflated configuration.

Clause 13: The assembly of Clause 12, wherein the lead bore of the implantable medical device comprises a contact that is electrically connected to the circuitry of the electronics module by a conductor, wherein a lead contact of the lead is configured to be electrically connected to the contact of the lead bore when the at least a portion of the lead is disposed within the lead bore.

Clause 14: The assembly of any one of Clauses 12-13, where the implantable medical device is an implantable defibrillator.

Clause 15: The assembly of any one of Clauses 12-13, where the implantable medical device is a neuromodulation device.

Clause 16: The assembly of any one of Clauses 12-15, further including a desiccant disposed within the housing.

Clause 17: The assembly of any one of Clauses 12-16, further including an inflation mechanism configured to be fluidly connected to the inlet of the lumen and manipulate the distal balloon between the deflated configuration and the inflated configuration.

Clause 18: The assembly of Clause 17, where the inflation mechanism includes a syringe or a pump.

Clause 19: The assembly of any one of Clauses 17-18, where the pressure sensor is connected to the inflation mechanism.

Clause 20: The assembly of any one of Clauses 12-19, where the pressure sensor includes an indicator balloon that defines a deflated configuration and an inflated configuration, where the indicator balloon is in the deflated configuration when the distal balloon is in the deflated configuration. The indicator balloon is in the inflated configuration when the distal balloon is in the inflated configuration.

Clause 21: The assembly of any one of Clauses 12-19, where the pressure sensor includes a disk and a base configured to receive the disk. A major surface of the disk faces a major surface of the base. The disk includes a first configuration and a second configuration. A first distance between a center portion of the major surface of the disk and the major surface of the base when the disk is in the first configuration as measured along a normal to the major surface of the disk and major surface of the base is less than a second distance between the center portion of the major surface of the disk and the major surface of the base when the disk is in the second configuration. The disk is in the first configuration when the distal balloon is in the deflated configuration and in the second configuration when the distal balloon is in the inflated configuration.

Clause 22: The assembly of any one of Clauses 12-19, where the pressure sensor includes a pressure transducer.

Clause 23: The assembly of any one of Clauses 12-19, where the pressure sensor includes an audible alarm.

Clause 24: The assembly of any one of Clauses 12-19, where the pressure sensor includes an indicator light. The indicator light is configured to emit light including a first wavelength when the distal balloon is in the deflated configuration and emit light including a second wavelength when the distal balloon is in the inflated configuration.

Clause 25: The assembly of any one of Clauses 12-19, where the pressure sensor includes a colored diaphragm and a frost lens. The colored diaphragm is configured to move in a direction normal to the diaphragm and frosted lens, wherein an area of contact between the colored diaphragm and the frosted lens corresponds to the pressure of the distal balloon.

Clause 26: The assembly of any one of Clauses 12-19, where the pressure sensor includes a mechanical switch. The signal includes a change of shape of the mechanical switch.

Clause 27: A method that includes inflating a distal balloon from a deflated configuration to an inflated configuration by expanding the distal balloon radially outward from an exterior surface of a lead body configured to extend through vasculature to a chamber of a heart of a patient; extending the distal balloon distally beyond a distal end of the lead body and proximal to a fixation member when the distal balloon inflates from the deflated configuration to the inflated configuration; and sensing a pressure within an interior volume of the distal balloon. The method further includes communicating a signal to a clinician that is indicative of the pressure within the interior volume of the distal balloon.

Clause 28: The method of Clause 27, further including substantially surrounding a portion of the fixation member with the distal balloon when the distal balloon inflates to the inflated configuration.

Clause 29: The method of any one of Clauses 27-28, where the lead body defines a lumen fluidly connected to the interior volume of the distal balloon at the distal end of the lead body. The lumen extends along the lead body between an inlet adjacent to a proximal end of the lead body and an outlet adjacent to the distal end of the lead body.

Clause 30: The method of Clause 29, where inflating the distal balloon includes connecting an inflation mechanism to the inlet of the lead body.

Clause 31: The method of any one of Clauses 29-30, where sensing the pressure includes fluidly connecting a pressure sensor to the lumen at the proximal end of the lead body, where communicating the signal indicative of the pressure includes communicating the signal indicative of the pressure within the interior volume of the distal balloon to the clinician utilizing the pressure sensor.

Clause 32: The method of Clause 31, where the signal includes a visual signal.

Clause 33: The method of Clause 32, where the pressure sensor includes an indicator balloon, where the visual signal includes an inflation volume of the indicator balloon.

Clause 34: The method of Clause 32, where the pressure sensor includes a pressure transducer.

Clause 35: The method of Clause 32, where the pressure sensor includes an indicator light.

Clause 36: The method of Clause 32, where the pressure sensor includes a disk and a base configured to receive the disk. A major surface of the disk faces a major surface of the base, where the signal includes a first configuration and a second configuration of the disk. A first distance between a center portion of the major surface of the disk and the major surface of the base when the disk is in the first configuration as measured along a normal to the major surface of the disk and major surface of the base is less than a second distance between the center portion of the major surface of the disk and the major surface of the base when the disk is in the second configuration. The disk is in the first configuration when the distal balloon is in the deflated configuration and in the second configuration when the distal balloon is in the inflated configuration.

Clause 37: The method of Clause 31, where the signal includes an audible signal.

The details of one or more aspects of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the techniques described in this disclosure will be apparent from the description and drawings, and from the claims.

The techniques of this disclosure generally relate to a medical lead system and an implantable medical device assembly that includes such lead system. The system can include a lead having a distal balloon connected to an exterior surface of a distal end of a lead body of the lead. The distal balloon can be fluidly connected to an outlet of a lumen of the lead. The system can also include a pressure sensor that is fluidly connected to an inlet of the lumen of the lead. The pressure sensor can be configured to sense pressure within an interior volume of the distal balloon and communicate a signal that is indicative of such pressure to a clinician. In one or more embodiments, the system can also include an inflation mechanism configured to be fluidly connected to the inlet of the lumen of the lead body and manipulate the distal balloon between the deflated configuration and the inflated configuration. The pressure sensor can include any suitable sensor. In one or more embodiments, the pressure sensor can include an indicator balloon that defines a deflated configuration and an inflated configuration. The indicator balloon can be in the deflated configuration when the distal balloon is in the deflated configuration. Further, the indicator balloon can be in the inflated configuration when the distal balloon is in the inflated configuration.

The medical lead system can be configured to transit through vasculature of the patient to position a distal portion of the lead body of the lead in the vicinity of a target area, such as an area within a chamber of the heart. For example, the medical lead system can be configured to allow a clinician to navigate the lead body through a vein of the heart (e.g., at least one of an innominate vein, an interior vena cava (IVC), or a superior vena cava (SVC)) to a target location within a right ventricle (RV), right atrium (RA), or another area of the heart. In one or more embodiments, the medical lead system is configured such that the distal balloon can be inflated within a vein of the heart enroute to the target area to, for example, minimize or eliminate physical interference between the fixation member and other anatomical structures as the medical lead system is transited within the patient.

The clinician may find it difficult to observe whether the distal balloon is the deflated configuration or the inflated configuration as it is disposed on the distal end of the lead when the lead is disposed within the patient's body, especially without the use of fluoroscopy or other imaging techniques. As a result, the clinician may not receive any feedback from the distal balloon as to whether it is in the inflated or deflated configuration. Further, the distal balloon may develop a leak while the lead is being advanced within the patient. Such leak would potentially go undetected by the clinician. If the distal balloon is not fully inflated as the lead is advanced within the patient, physical interference between the fixation member of the lead and other anatomical structures can occur.

One or more embodiments of the present disclosure can provide various advantages over currently available lead systems. For example, the pressure sensor of the medical lead system can be configured to sense the pressure within the interior volume of the distal balloon and communicate the signal indicative of such pressure to the clinician. Such signal can, for example, indicate to the clinician whether the distal balloon is the inflated or deflated configuration, or whether the balloon is losing pressure due to a leak. The pressure sensor can include any suitable type of pressure sensor, e.g., at least one of a mechanical, electrical, auditory, or visual sensor. Further, one or more embodiments of a medical lead system of the present disclosure can include an inflation mechanism that is configured to be fluidly connected to the inlet of the lumen of the lead body and manipulate the distal balloon between the deflated configuration and the inflated configuration.

In general, the distal balloon can be configured to expand radially outward from the lead body when the balloon is inflated from the deflated configuration to the inflated configuration. Further, in one or more embodiments, the distal balloon can be configured to define a substantially toroidal shape around the lead body in the inflated condition such that, for example, the lead body extends through the toroid hole. In one or more embodiments, the fixation member is configured to extend through the toroid hole. In one or more embodiments, the distal balloon is configured to expand around the distal portion of the lead body such that a blood flow imparts a force on the balloon in the direction of the blood flow (e.g., such that the balloon acts as a “sail”). The distal balloon can be configured to transmit the force to the lead body to assist in transiting the lead body through the vasculature and/or a heart chamber of the patient while substantially shrouding the fixation member. In one or more embodiments, the distal balloon is configured to inflate to an expanded dimension (e.g., a diameter) of at least twenty times a diameter of the lead body. In one or more embodiments, the lead body defines an inner lumen configured to deliver an inflating medium to cause inflation of the distal balloon.

The medical lead system can be configured to electrically communicate with tissue within a patient when the distal balloon is in the inflated configuration. In one or more embodiments, the fixation member mechanically supports an electrode configured to electrically communicate with the tissue. The fixation member can be configured to position the electrode to communicate with the tissue when the fixation member extends distal to the inflated balloon. In one or more embodiments, the fixation member is configured to allow the electrode to contact the tissue when the fixation member extends distal to the inflated balloon. The medical lead system can include a conductor in electrical communication with the electrode. In one or more embodiments, the medical lead system includes processing circuitry configured to deliver therapy to the tissue using the conductor and the electrode. The medical lead system may be configured such that a clinician can perform cardiac mapping using the electrode while the balloon is inflated, such that the cardiac mapping may occur as the balloon substantially shrouds the fixation member to reduce and/or eliminate physical interferences between the fixation member and surrounding anatomical structures.

The distal balloon is configured to deflate from the inflated configuration to substantially re-establish the deflated configuration. For example, a clinician may cause the balloon to substantially re-establish the deflated configuration (e.g., by venting the balloon through the lumen) to secure the medical lead system to the tissue using the fixation member. In one or more embodiments, the fixation member defines a helix extending distal to the lead body distal end and at least partially shrouded by the distal balloon. The clinician may deflate the balloon via the lumen to cause the balloon to deflate and withdraw proximal to the lead body distal end, such that the fixation member is substantially unshrouded. The clinician may then cause the helix to substantially engage the tissue by, for example, torquing the lead body around a longitudinal axis to drive the helix into a surface of the tissue. The distal balloon may be configured to remain affixed to the lead body and proximal to the fixation member and/or electrode in the deflated configuration, such that processing circuitry may deliver therapy to the patient via the electrode with the balloon in the deflated configuration.